Drug police in the Siberian city of Tomsk have discovered a new drug made of a substance used to repair tires, which they say may affect human brain more severely than heroin.

The newly discovered drug, dubbed “zhgut” (twist), looks like a smoking blend, Igor Tolstonogov, the Tomsk drug police chief said on Tuesday.

“The substance is distributed without advertisement among a small group of people,” Tolstonogov told journalists, adding: “Our research and surveys among drug users and specialists show that the impact of this substance on the human brain may be worse than that of heroin.”

Tolstonogov said he had requested the Federal Drug Control Service include the drug in the list of banned substances, which would allow initiating criminal cases against its traffickers and users.

The drug police will rely on its previous experience of banning a recently discovered drug called “rastishishka,” he added.